title: Increased prevalence of symptoms of rhinitis but not of asthma between 1990 and 2008 in Swedish adults: comparisons of the ECRHS and GA²LEN surveys.
abstract: BACKGROUND
  The increase in asthma prevalence until 1990 has been well described. Thereafter, time trends are poorly known, due to the low number of high quality studies. The preferred method for studying time trends in prevalence is repeated surveys of similar populations. This study aimed to compare the prevalence of asthma symptoms and their major determinants, rhinitis and smoking, in Swedish young adults in 1990 and 2008.
  
  
  METHODS
  In 1990 the European Community Respiratory Health Survey (ECRHS) studied respiratory symptoms, asthma, rhinitis and smoking in a population-based sample (86% participation) in Sweden. In 2008 the same symptom questions were included in the Global Allergy and Asthma European Network (GA(2)LEN) survey (60% participation). Smoking questions were however differently worded. The regions (Gothenburg, Uppsala, Umeå) and age interval (20-44 years) surveyed both in 1990 (n = 8,982) and 2008 (n = 9,156) were analysed.
  
  
  RESULTS
  The prevalence of any wheeze last 12 months decreased from 20% to 16% (p<0.001), and the prevalence of "asthma-related symptoms" was unchanged at 7%. However, either having asthma attacks or using asthma medications increased from 6% to 8% (p<0.001), and their major risk factor, rhinitis, increased from 22% to 31%. Past and present smoking decreased.
  
  
  CONCLUSIONS
  From 1990 to 2008 the prevalence of obstructive airway symptoms common in asthma did not increase in Swedish young adults. This supports the few available international findings suggesting the previous upward trend in asthma has recently reached a plateau. The fact that wheeze did not increase despite the significant increment in rhinitis, may at least in part be due to the decrease in smoking.
authors.affiliation: The OLIN Studies, Department of Medicine, Sunderby Central Hospital of Norrbotten, Luleå, Sweden. anders.bjerg@lung.umu.se
authors.forename: Anders
authors.initials: A
authors.lastname: Bjerg
authors.forename: Linda
authors.initials: L
authors.lastname: Ekerljung
authors.forename: Roelinde
authors.initials: R
authors.lastname: Middelveld
authors.forename: Sven-Erik
authors.initials: SE
authors.lastname: Dahlén
authors.forename: Bertil
authors.initials: B
authors.lastname: Forsberg
authors.forename: Karl
authors.initials: K
authors.lastname: Franklin
authors.forename: Kjell
authors.initials: K
authors.lastname: Larsson
authors.forename: Jan
authors.initials: J
authors.lastname: Lötvall
authors.forename: Inga Sif
authors.initials: IS
authors.lastname: Olafsdóttir
authors.forename: Kjell
authors.initials: K
authors.lastname: Torén
authors.forename: Bo
authors.initials: B
authors.lastname: Lundbäck
authors.forename: Christer
authors.initials: C
authors.lastname: Janson
mesh_terms: D000328:Adult; D000402:Airway Obstruction / Q000453:epidemiology / Q000209:etiology; D001249:Asthma / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D016208:Databases, Factual / Q000706:statistics & numerical data; D005060:Europe / Q000453:epidemiology; D005260:Female; D006306:Health Surveys / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D015995:Prevalence; D012135:Respiratory Sounds / Q000175:diagnosis / Q000502:physiology; D012220:Rhinitis / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D015854:Up-Regulation; D055815:Young Adult